Put simply, the answer to the question "what is meditation" is the practice of constant focus on something. It can be a sound - such as repeating a mantra, an object - such as a candle flame, your own breath or anything else that gives you a point to focus your attention on.
Of course,anything that sounds that simple sets our mind racing for the answer to the next question: "Is it really that easy?" We tend to assume that things are always complicated but that's actually not the case with meditation. At its most basic, meditation involves focusing on just one thing at a time.
There'll be distractions - maybe sounds or smells that you've never noticed before because you've been so busy concentrating on everything else in your life. But you can bring your attention back to whatever it is that you're focusing on quite easily as soon as you find yourself drifting.
There are lots of different methods of meditating. Some are as simple as noticing your breathing, others are slightly more complicated and yet others simply involve listening to a specially recorded audio file, often with binaural beats to aid your brain's move towards a deep meditative state.
There are pros and cons with each of the methods and my usual advice is to try several different meditation methods until you find one that works best for you. We're all individuals, so don't worry if a method that someone else raves about leaves you stone cold. Most methods are cheap to try out so don't be afraid to experiment.
The answer to the question of if it is worth your time learning to meditate is ultimately only for you to answer. Which sounds like a cop out but no matter how much I try to persuade you that a particular meditation is best for you, if you decide otherwise then that will be the real answer as far as you are concerned.
That said, there are a number of benefits that are common to pretty much all the different kinds of meditation.
A sense of inner calm and relaxation is one of the most frequently reported benefits. In turn, this can have positive "knock on" effects on your health. Some of this can be accounted for by the reduction in stress levels that are achieved when you are generally more calmer and more relaxed. Studies are difficult in this area as - by definition - they can't comply with the rigors of double blind testing that modern medicine likes to see. But a large number of people report that their blood pressure has dropped along with their stress levels.
The easiest way to find out whether this will be one of the benefits you get from regular meditation is to try it. It's cheaper than buying over the counter medicines and it's totally natural.
For me, I find that I'm generally less stressed and a happier person than I was before I started to meditate on a regular basis. People who've known me for some years tend to agree with this.
Even if you can only spare the time to meditate a couple of times a week, I think you'll find the benefits begin to show up in the rest of your life. You owe it to yourself to give meditation a try!